Osteoporosis is a prevalent disease with widespread devastating clinical consequences. Treatment to date has involved agents which by and large prevent bone loss rather than induce new bone formation; thus we have obvious limitations in treatment options for the patient with established disease. No safe effective bone forming agent has yet to be approved for the treatment of this disease. The purpose of this study is to test the safety and efficacy of Low Dose Doxycycline for stimulation of bone formation in postmenopausal women with osteoporosis.